It might have no effect at all. We do not know since you have not told us much.
SALE OF A HOUSE
If your gain was more than $250,000 filing Single, or more than $500,000 filing Married Filing Jointly the sale must be reported on your tax return. Whether you re-invested the gain in to another house is irrelevant. If you have a Form 1099-S go to Federal>Wages and Income>Less Common Income>Sale of Home (gain or loss)
If you owned and lived in the home as your primary residence for at least 2 of the last 5 years on the date of the sale, you do not have to report the home sale if the gain is less than $250K filing Single, or less than $500K filing Married Filing Jointly (and you both owned and lived in the home for at least 2 years).
As for the house you purchased, buying a house is not something you report on a tax return, but you can enter the mortgage interest, property tax and loan origination fees paid n 2018 if you are itemizing deductions.
It is going to be very hard for a lot of people to use itemized deductions now that the standard deduction is so much higher. Your home ownership may not have any effect on your tax due or refund, especially if you purchased the house late in the year.
Your itemized deductions have to be more than your standard deduction before you will see a change in your tax owed or tax refund. The deductions you enter do not necessarily count “dollar for dollar;” many of them are subject to meeting tough thresholds—medical expenses, for example, must meet a threshold that is pretty hard to reach. The software program uses all the IRS rules that apply to the expenses you enter, and it tells you if you have enough to use your itemized deductions or if using the standard deduction is more advantageous for you. Under the new tax laws, some deductions have been capped—there is a $10,000 limit to the itemized deductions for state, local, property and sales taxes.
2018 Standard Deductions:
Single $12,000 (+ $1600 65 or older)
Married Filing Separately $12,000 (+ $1300 65 or older)
Married Filing Jointly $24,000 (+ $1300 each spouse 65 or older)
Head of Household $18,000 (+ $1600 65 or older)
There is not a first time home buyers credit on a Federal return. That ended in 2010. If your state has such as credit, you will be able to enter it when you prepare your state return.
Buying a home is not a guarantee of a big refund. Your deductions for homeownership combined with your other deductions (if any) must exceed your standard deduction to change your tax due or refund. If you purchased your home late in the year, you do not even have a full year of home ownership deductions.
Your closing costs on your new home are not deductible except for prepaid interest, prepaid property tax or loan origination fees. There are no deductions for appraisal, inspections, title searches, settlement fees. etc.
Your down payment is not deductible.
Your homeowners insurance for fire, hazard, flood, etc. is not deductible for your own home.
Home improvements, repairs, maintenance, etc. for your own home are not deductible.
Homeowners Association (HOA) fees for your own home are not deductible.